Novel Energy Scale in the Interacting 2D Electron System Evidenced from Transport and Thermodynamic Measurements

Abstract

We study how the non-Fermi-liquid two-phase state reveals itself in transport properties of high-mobility Si-MOSFETs. We have found features in zero-field transport, magnetotransport, and thermodynamic spin magnetization in a 2D correlated electron system that may be directly related with the two-phase state. The features manifest above a density dependent temperature $T^{\ast }$ that represents a novel high-energy scale, apart from the Fermi energy. More specifically, in magnetoconductivity, we found a sharp onset of the novel regime $\delta \sigma (B,T)\propto (B/T{)}^2$ above a density-dependent temperature $T_{\mathrm{kink}}(n)$, a high-energy behavior that "mimics" the low-temperature diffusive interaction regime. The zero-field resistivity temperature dependence exhibits an inflection point $T_{\mathrm{infl}}(n)$. In thermodynamic magnetization, the weak-field spin susceptibility per electron, $\partial \chi /\partial n$ changes sign at $T_{dM/dn}(n)$. All three notable temperatures, $T_{\mathrm{kink}}$, $T_{\mathrm{infl}}$, and $T_{dM/dn}$, behave critically $\propto (n-n_c)$, are close to each other, and are intrinsic to high-mobility samples solely, we therefore associate them with an energy scale $T^{\ast }$ caused by interactions in the 2DE system.

arXiv admin note: substantial text overlap with arXiv:1506.07326

References in corpus (7)

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• Coulomb Correlations and the Wigner-Mott Transition
• Spin-Droplet State of an Interacting 2D Electron System
• Two-dimensional metal-insulator transition and in-plane magnetoresistance in a high mobility strained Si quantum well
• Intervalley scattering and weak localization in Si-based two-dimensional structures
• Signatures of localization in the effective metallic regime of high mobility Si MOSFETs
• Quantum phase transitions in two-dimensional systems